As relevant and influential today as when it was first published, this classic exposition of evolutionary thought stimulated whole new areas of research. This 50th anniversary edition includes a new epilogue by the author and a new appendix on the work of British zoologist A.G. Lowndes in the 1930s.

As relevant and influential today as when it was first published, this classic exposition of evolutionary thought stimulated whole new areas of research. This 50th anniversary edition includes a new epilogue by the author and a new appendix on the work of British zoologist A.G. Lowndes in the 1930s.